Sewing machines



May 30, 1961 Filed May 9, 1958 W. T. MAXANT SEWING MACHINES 2 Sheets-Sheet 1 W WILL/AM 7." MAXANT ATTORNEYS y 1961 w. T. MAXANT 2,986,105

SEWING MACHINES Filed May 9, 1958 2 Sheets-Sheet 2 WILL/AM T MAXANT ATTORNEYS SEWING MACHINES William T. Maxant, Chandler Machine Co., Ayer, Mass.

Filed May 9, 1958, Ser. No. 734,223

3 Claims. (Cl. 112-76) This invention relates to sewing machines, and more particularly to clamp lifter mechanisms for button sewing machines.

Specialized sewing machines for attaching various articles, such as buttons, to cloth and the like, are used extensively by commercial fabricators of clothing and other goods. Such a machine is disclosed in my prior Patent No. 2,563,854, granted August 14, 1951. These machines include clamp means for holding the button in position with respect to the fabric to which it is to be attached, and for shifting the work relative to the sewing instrumentalities so that suitable stitches may be formed to secure the button to the fabric. After a sewing cycle has been completed, the clamp means is raised relative to the base of the machine so as to break the thread and permit withdrawal of the goods from the machine. Then, a new button is disposed in the clamp, the clamp is lowered, and a new cycle is initiated.

In my prior patent identified above, I disclosed a treadle for actuating the clamp means in the proper manner. When a treadle is used, the operator has good control over the functioning of the clamp means, in that he may time the opening and closing of the clamp means to suit the particular operation being performed and in that he may vary the amount of clamp lift in accordance with his own wishes. However, it has been recognized that the use of a treadle for lifting the clamp means imposes additional burdens upon the operator. He must be trained thoroughly and he must exercise judgment repeatedly if production is to proceed smoothly.

Accordingly, it is an object of this invention to provide such a sewing machine with a clamp lifting mechanism which may be operated automatically when desired. During automatic operation, the clamp means will be lifted at the end of each sewing cycle and then lowered at the beginning of the next cycle without requiring the attention of the operator. This added convenience materially simplifies the task of the operator and increased production may be expected.

it is another object of this invention to provide an improved automatic clamp lifting mechanism for a button sewing machine, which mechanism may be adjusted as to the timing of the clamp lifting operations and as to the throw of the clamp.

Yet another object of this invention is to provide a button sewing machine with a novel clamp lifting mechanism which may be operated automatically or manually, and in which manual control may be exercised at any time during a sewing cycle without interfering with the means for automatically actuating the clamp at the end of the cycle.

The foregoing objects may be accomplished according to a preferred embodiment of the invention, by provid ing the clamp lifting mechanism of a button sewing machine with an actuating element connected to both a manually operable device and a device operable by cam means driven by the main drive shaft of the machine. When the "nited States Patent 2,986,10 Patented May 30, .1961

actuating element is moved by either of these devices, it serves to operate the button clamp.

The manually operable device may be a treadle mechani ically connected to the actuating element of the clamp lifting mechanism in such a way that the treadle may be operated to raise the button clamp at any time and to any desired elevation. This arrangement gives the operator complete control of the machine, and gives a degree of flexibility which is of considerable importance in some production operations.

The other device for moving the actuating element of the clamp lifting mechanism includes a cam follower and an adjustable linkage connecting the follower to the actuating element. The cam means for tn'ppingthe cam follower is itself adjustable so that the operator may obtain the desired timing for clamp operation. Moreover, the adjustments in the linkage connecting the cam follower to the actuating element of the mechanism are of such a nature that the throw of the clamp may be regulated or the follower may be removed entirely from the path of the cam means when automatic operation is not desired.

A better understanding of the construction of the present invention and its many advantages will be gained from a consideration of the following detailed description of an embodiment thereof illustrated in the accompanying drawings, in which:

Fig. 1 is a side elevational view of a button sewing machine embodying the invention;

Fig. 2 is a similar side elevational view showing the parts of the machine in the poistions they occupy at the end of a sewing cycle;

Fig, 3 is a bottom plan view of the operating mechanisms disposed in the base of the machine of Fig. 1;

Fig. 4 is a similar bottom plan view of the operating mechanisms, but it illustrates the positions of the parts at the conclusion of a sewing cycle and may be thought of as corresponding to Fig. 2; and

Fig. 5 is a partial, vertical cross sectional view illustrating the drive for the cam assembly in the base of the machine of Fig. 1.

The button sewing machine illustrated in Figs, 1 and 2 of the drawings conforms generally to that disclosed in my prior patent identified above. It includes a base 2 having a lower section 4 and an upper section 6 hingedly connected together along the side of the machine opposite that shown in Figs. 1 and 2, so that the base 2 may be opened when it is desired to gain access to the operating mechanisms disposed therein. It will be understood, of course, that the base 2 normally rests upon and is supported by a suitable work table or the like (not illustrated) so that the machine will be at a convenient level for actuation by an operator. 1 p

Extending upwardly from the base 2 is a hollow stand ard 8 which carries a hollow, laterally extending, arm 10 at its upper end. The free end of the arm 10 serves to support a conventional sewing head 12, which may be of the construction disclosed in my prior patent identified above. A needle bar 14 is mounted for vertical reciprocation within the sewing head 12 and is driven by means well known in the art. A sewing needle 16, attached to the needle bar 14, reciprocates vertically so that its lower end may move through an opening 18 (Fig. 3) in a lateral extension 20 of the upper section 6 of the base 2 of the machine. It will be understood that suitable stitch-forming means, such as a looper and a thread finger, are disposed within the lateral extension 20 in position to cooperate with the needle 16 to form stitches in the usual fashion.

A button clamp unit, designated generally by the numeral 22, is mounted upon the top wall of the base 2, for holding a button in position for cooperation with the a stitch-forming means. This unit 22 includes a bottom plate 24 slidably mounted upon the top wall of the base 2 for horizontal movements relative to said wall, a clamp arm 26 pivotally connected to the bottom plate 24 by a pin 28, and a clamp underjaw 30 pivotally connected to the arm 26 as suggested by the numeral 32. At its forward end, the clamp arm 26 carries a forwardly directed, button-holding, clamp jaw 34 which cooperates with the underjaw 30 to hold a button in operative position with respect to the needle 16 and a piece of fabric to which the button is to be attached.

The sewing machine also may include a number of other instrumentalities disclosed more fully in my prior patent identified above. For example, it may be provided with a thread clamp 36 adjacent the face plate 38 of the sewing head 12, thread slack take-off means 40, and suitable thread tensioning means 42. These instrumentalities form no part of the present invention, and they need not be described in detail.

Power for operating the machine is supplied by a drive belt (not illustrated) which cooperates with a drive pulley 44 fixed on a drive shaft 46 protruding from the end of the base 2 opposite that at which the extension is located. Since the machine operates in definite, predetermined, button sewing cycles, it also must be provided with a suitable stop motion for immobilizing the drive shaft 46 at the conclusion of a cycle so that a new button may be brought into position with respect to the clamp jaw 34. Although this stop motion may be conventional, certain parts of it are illustrated in the drawings for the sake of completeness, and these will be referred to hereinafter. It will suffice at this point to note that Figs. 1 and 3 represent positions assumed by the various parts of the machine during operating cycles and that Figs. 2 and 4 represent the positions of the parts during an interval between cycles.

Referring particularly to Fig. 2, it will be seen that at the conclusion to a sewing cycle, the clamp arm 26, along with the button-holding clamp jaw 34, moves upwardly away from the base 2 of the machine. Such movement breaks the sewing thread to free the already attached button and the fabric from the machine. After this button has been removed from the clamp jaw 34, a new button may be placed in the jaw, and a diiferent fabric portion may be located in the space between the clamp jaw 34 and the underjaw of the clamp unit 22. A new sewing cycle then may be initiated by lowering the clamp arm 26 and by setting the sewing instrumentalities in motion.

The present invention is concerned primarily with the mechanism for lifting and lowering the clamp arm 26 in the desired manner. This mechanism includes a link 48, the lower end of which is pivotally connected at 50 to the clamp arm 26 and the upper end of which is pivotally connected at 52 to one arm of a bell crank 54. The bell crank 54 is disposed within the hollow arm 10 of the sewing machine so as to protrude downwardly through a slot in the bottom of such arm. It is pivotally connected to the arm 10 by means of a suitable pivot pin 56.

The other arm of the bell crank 54 is pivotally connected at 58 to a link or strap member 60 extending horizontally through the hollow arm 10 of the machine and being connected at its rear end to a crank 62. The forward end portion of the strap 60 has mounted thereon a thread slack kick pin 64 for operating the device 40 at the conclusion of each operating cycle of the machine. As explained in my prior patent identified above, the thread slack kick pin 64 should be mounted for linear adjustment along the strap 60 in order that the amount of slack may be controlled properly.

The crank 62 is pivotally mounted at 66 in the standard 8 of the machine, and its other arm is pivotally connected at 68 to a vertically extending actuating element or link 70. When the actuating element 70 is moved downwardly from the position shown in Fig. 1 to the position shown in Fig. 2, the crank 62 swings about its pivot 66 to move the horizontal link 60 to the tight, as viewed in Figs. 1 and 2. This movement, in turn, causes the bell crank 54 to swing about its pivot 56 in a clockwise direction to raise the link 48 and the clamp arm 26. Then, when the actuating element 70 is moved upwardly again, the several parts of the linkage means are moved in reverse directions to return the clamp arm 26 to its lowermost position.

The actuating element 70 extends downwardly through an opening 71 in the upper wall of the base 2 of the machine for operation by devices located within, or at least having connections extending into, the interior of the base 2. A pivot pin 72 is provided for connecting the lower end of the actuating link 70 to a crank 74 pivotally mounted at 76 on a lug 77 depending from the top wall of the base 2 for swinging movements in a vertical direction about a horizontal axis. A tension spring 78 is connected to the crank 74 for biasing it in a direction tending to move the actuating link 70 upwardly. Thus, the normal position of the clamp arm 26 is that illustrated in Fig. l. In order to move it from the position shown in Fig. l to the position shown in Fig. 2, forces must be applied to the crank 74 to overcome the bias of the spring 73.

Manual control over the movements of the actuating link 70 is achieved by connecting a chain 80, or other suitable means, to the pivot pin 72 at the lower end of the link '70. This chain 80 extends downwardly through an opening 81 in the lower wall of the base 2 of the machine and its lower end preferably is connected to a treadle or some other conventional device which will enable the operator to pull downwardly on the chain 80 when desired.

Means for automatically operating the actuating element 70 also is provided. Such means is illustrated best in Figs. 1, 3, and 4, and particular reference thereto is invited.

The arm of the crank 74 opposite that to which the actuating link 70 is connected has mounted thereon a laterally extending stud 82. This stud is fixed with respect to the crank 74 and has a threaded end portion 84 of reduced diameter disposed in horizontally spaced relation with respect to the crank 74. A connecting strap or link 86 having an enlarged flat end portion 38 is disposed adjacent to the threaded end portion 84 of the stud 82 for cooperation therewith. As best shown in Fig. 1, the flat portion 88 of the strap 86 has two horizontal openings 90 and 92, each of which is of a size such that the threaded end portion 84 of the stud 82 may pass therethrough. When the stud has been located in one of the openings 90 or 92, the strap 86 may be secured in position on the stud 82 by a suitable nut 94 engaging the threaded end portion 84 of the stud 82, and serving to restrain the fiat end portion 88 of the strap 86 against movement over the end of the stud 82.

The end portion of the connecting strap 86 opposite the flat portion 88 passes through an aperture 95 in a lever 96 mounted on the top of the base for swinging movements about a vertical axis 98. The aperture 95 is enlarged so that the lever 96 may swing relative to the connecting strap 86 without binding. Normally, however, it is intended that the connecting strap 86 move with the lever 96. To this end, the end 100 of the connecting strap 86 is threaded and receives an adjustment nut 101 of greater diameter than the aperture 95 and a check nut 103. The lever 96 is held against the nut 101 by a compression spring 102 surrounding the strap 86.

The opposite end of the lever 96 has secured thereto a bracket 104 which projects laterally away from the lever 96 in the manner shown in Figs. 3 and 4. At its outer end, the bracket 104 carries a roller 106, or other suitable means, for cooperating with a cam 108 adjustably mounted upon a rotatable disk 110. The roller 10.6 serves as a cam follower. When thev disk 110 is rotated, the earn 108 moves along a path such that it may contact the roller 106 in the manner suggested in Figs. 3 and 4, to shift the roller 106 horizontally away from the axis of rotation of the disk 110.

When the cam follower roller 106 moves outwardly, the lever 96 moves with it to shift the connecting strap 86 to the left, as viewed in Figs. 3 and 4. This causes the stud 82 to move to the left and swing the crank 74 about its axis 76 so as to exert a downward pull on the actuating link of the crank lifting mechanism. Hence, the positions of the parts illustrated in Fig. 4 are those assumed when the clamp arm 26 of the button clamp unit 22 has been raised through the action of the cam 108.

The rotatable disk forms a part of the regular control system for the sewing machine, and reference may be made to my prior patent identified above for a more complete disclosure of this component. It is attached by a screw 112 to a stud 114 depending from the top wall of the base 2 of the machine and is rotatable relative to the stud 112. Other screws 116 pass through the disk 110 and secure thereto the cam assembly for controlling the operation of the machine. The cam assembly also includes a hub member 118 having a worm wheel 120 near its upper end in position for actuation by a worm 122 on the drive shaft 46, so that the disk 110 rotates whenever the drive shaft 46 rotates.

Although the operating mechanisms for the machine illustrated in the drawings may be conventional, it may be helpful to refer briefly to certain components illustrated in Figs. 3 and 4 of the drawings. In these views, the left hand portion of the drive shaft 46 terminates in the extension 20 of the base 2 of the machine, and it will be understood that this end portion of the drive shaft has mounted thereon a rotary shuttle, or the like, for cooperating with the needle 16 to form stitches. Reciprocation of the needle 16 is brought about by a linkage extending through the arm 10 and the standard 8 of the machine, and cooperating with an eccentric on the drive shaft 46. In Figs. 3 and 4 there is illustrated a bearing unit 124 which surrounds the eccentric on the drive shaft 46 and is connected to the needle-driving linkage.

Cyclical operation of the machine is brought about by stop motion which includes a stop shaft 126 mounted in the upper section 6 of the base 2 for longitudinal sliding movements. A tension spring 128 biases the stop shaft 126 toward the right, as viewed in Figs. 3 and 4, but during machine cycles, the stop shaft 126 is held against movement under the influence of the spring 128 by a latch 130 cooperating with an abutment 132 on the stop shaft 126. The latch 130 is opened automatically at the end of each cycle by a control cam connected to the disk 110, so that the stop shaft 126 then is free to move to the right under the influence of the spring 128. During longitudinal movements of the stop shaft 126, it is restrained against rotation by a guide stud 134 fixed to the base section 6 and cooperating with guide arms 136 and 138 fixed to the stop shaft 126. A bumper 140 also is fixed to the stop shaft 126 to cushion the impact of the components as they move to the right under the influence of the spring 128.

On the exterior of the base section 6, the stop shaft 126 carries a belt shifter unit 142 and a latch unit 144. The belt shifter unit 142 operates, when the stop shaft 126 moves to the right, to shift the drive belt of the machine from the drive pulley 44 to an idler pulley 146 rotatably mounted upon the drive shaft 46, so that the drive belt may continue to run even though the drive shaft 46 is immobilized. The latch unit 144 cooperates with an abutment 14*8 rigidly connected to the drive shaft 46. In the positions of the parts shown in Fig. 3, the latch unit 144 is displaced laterally from the path of the abutment, but when the stop shaft 126 moves to the right, the latch unit 144 comes into position adjacent the abutment 148 so that the abutment 148 may be engaged thereby to lock the shaft 46 in a predetermined angular position.

Other control devices suggested by Figs. 3 and 4 are means for operating the thread clamp 36 and means for shifting the base plate 24 of the thread clamp unit 22 horizontally. The thread clamp 36 is actuated at the conclusion of the sewing cycle by a linkage tripped by a lever 150 under the control of the cam assembly carried by the disk 110. Similarly, the horizontal movements of the base plate 24 of the button clamp unit 22 necessary for shifting the button so as to present different button holes to the line of movement of the needle 16 are controlled by elements such as 152 operatively associated with the cam assembly.

Thus, it will be seen that the elements carried by the disk 110 constitute a complete control assembly. All of the control functions required for the button sewing operations may be carried out at this one location, and this location is conveniently located in the interior of the base 2 of the machine. Since the automatic clamp lifting operations must occur in a precise time relationship with respect to the other operations of the machine, it is important that the earn 108 be adjustable with respect to the disk 110. In the illustrated embodiment'of the invention, this result is accomplished by attaching the cam 108 to the disk by two screws 154 and 156, which threadedly engage holes in the disk 110 and clamp the cam 108 against the lower face of the disk 110. The screw 154 passes through a circular hole 158 in the cam 108, but the screw 156 passes through an arcuate slot 160 in the cam 108. Therefore, when the screws 154 and 156 are loosened slightly, the cam 108 may be swung about the axis of the screw 154 to adjust its location relative to the axis of rotation of the disk 110. In this manner, the timing of the clamp opening operation may be controlled with precision.

It should be recognized also that'the amount of lift imparted to the clamp arm 26 of the clamp button unit 22 is a factor which must be varied in accordance with the particular sewing operations being performed and the desires of the operator of the machine. In the illustrated construction, the amount of clamp lift may be controlled by adjustments of the nuts 101 and 103 on the threaded end portion 100 of the connecting strap 86. As the nut 101 is rotated so as to move it bodily to the right, as viewed in Figs. 3 and 4, the spring 102 will be compressed further and the lever 96 will swing in a clockwise direction. This brings the cam follower roller 106 closer to the axis of rotation of the disk 110. As a result, the effective throw of the cam 108 is increased, and the clamp arm 26 of the button clamp unit 22 will be raised to a greater extent. After an adjustment has been made, the nut 101 may be locked in position by manipulating the check nut 103.

For some operations, it is desirable that the automatic clamp lifting action be discontinued entirely. The present invention provides for such contingencies by the manner in which the connecting strap 86 is attached to the operating crank 74 for the actuating link 70 of the clamp lifting mechanism. When it is desired to render the lever 96 inoperative, all that need be done is to relocate the flat portion 88 of the connecting strap 86 so as to bring the hole 92 in the strap into position upon the threaded end portion of the stud 82. With the parts in such positions, the cam follower 106 will be held entirely out of the path of the cam 108. As will be evident, the relocation of the strap 86 with respect to the stud 82 may be accomplished by removing the nut 94, shifting the strap portion 88 to the left, and then reapplying the nut 94 after the end portion 84 of the stud 82 has been passed through the hole 92.

One other feature of the present invention will be evident from a careful study of Fig. 3. It will be noted that the cam follower. 106 is free to move outwardly at all times, Therefore, it is always possible to raise the clamp arm 26 of the button clamp unit 22 by manipulation of the treadle chain 80. If, for example, it should become desirable to raise the button clamp slightly during a sewing cycle, the operator may do so without interference from the automatic clamp lifting mechanism. This gives the machine a flexibility which is highly desirable.

Although a single embodiment of the invention has been illustrated and described in detail, various modifications and alterations will be apparent to persons skilled in the art. It is intended, therefore, that the foregoing description be considered exemplary only and that the scope of the invention be ascertained from the following claims.

I claim:

1. In a button sewing machine having a hollow base, a hollow standard extending upwardly from said base, a hollow arm extending laterally from the upper end of said arm, a sewing head on the free end of said arm,

cooperating sewing instrumentalities in said base and said head for forming stitches, a drive shaft extending through said base and being operatively connected to said sewing instrumentalities, a cam assembly in said base driven by said drive shaft, means cooperating with said cam assembly to cause said instrumentalities to operate in predetermined button-sewing cycles, a button clamp unit disposed upon the upper surface of said base and including a vertically movable clamp member for holding a button in position with respect to said sewing instrumentalities, and a linkage connected to said clamp member and extending through said arm and said standard to the interior of said base, the improvement which comprises a cam mounted on said cam assembly, a lever pivotally mounted in said base, a cam follower fixed to said lever for cooperating with said cam to move said lever, a crank pivotally mounted in said base and being connected to said linkage, and adjustable means connecting said lever to said crank for moving said crank a regnlatable amount in response to the movement of said lever which occurs when said cam follower is actuated by said cam, whereby said clamp member may be lifted different amounts and to different elevations.

2. In a button sewing machine having a hollow base, a hollow standard extending upwardly from said base, a hollow arm extending laterally from the upper end of said arm, a sewing head on the free end of said arm, cooperating sewing instrumentalities in said base and said head for forming stitches, a drive shaft extending through said base and being operatively connected to said sewing instrumentalities, a cam assembly in said base driven by said drive shaft, means cooperating with said cam assembly to cause said instrumentalities to operate in predetermined button-sewing cycles, a button clamp unit disposed upon the upper surface of said base and including a vertically movable clamp member for holding a button in position with respect to said sewing instrumentalities, and a linkage connected to said clamp all member and extending through said arm and said standard to the interior of said base, the improvement which comprises a cam mounted on said cam assembly, a lever pivotally mounted in said base, a cam follower fixed to said lever for cooperating with said cam, a crank pivotally mounted in said base and being connected to said linkage, means biasing said crank toward a first position in which said clamp member is lowered, connector means connecting said lever to said crank for transmitting motion therebetween, said connector means being adjustable to vary the distance between said lever and said crank to such an extent that said cam follower may be positioned selectively either in or out of the path of said cam when said crank is in said first position, and manually operable means connected to said linkage and extending out of said base for actuating said clamp member manually.

3. In a button sewing machine having a hollow base, a hollow standard extending upwardly from said base, a hollow arm extending laterally from the upper end of said arm, a sewing head on the free end of said arm, cooperating sewing instrumentalities in said base and said head for forming stitches, a drive shaft extending through said base and being operatively connected to said sewing instrumentalities, a cam assembly in said base driven by said drive shaft, means cooperating with said cam assembly to cause said instrumentalities to operate in predetermined button-sewing cycles, a button clamp unit disposed upon the upper surface of said base and including a vertically movable clamp member for holding a button in position with respect to said sewing instrumentalities, and a linkage connected to said clamp member and extending through said arm and said standard to the interior of said base, the improvement which comprises a cam mounted on said cam assembly, means adjusting said cam for angular adjustment relative to said cam assembly, a lever pivotally mounted in said base, a cam follower fixed to said lever for Cooperating with said cam to move said lever, a crank pivotally mounted in said base and being connected to said linkage, and adjustable means connecting said lever to said crank for moving said crank a regulatable amount in response to the movement of said lever which occurs when said cam follower is actuated by said cam, whereby said clamp member may be lifted diflerent amounts and to different elevations.

References Cited in the file of this patent UNITED STATES PATENTS 1,358,855 Kiewicz Nov. 16, 1920 2,175,612 Lyons Oct. 10, 1939 2,242,688 Unger May 20, 1941 2,266,081 Rogers Dec. 16, 1941 2,300,585 McCann Nov. 3, 1942 2,558,679 Gressel et al June 26, 1951 2,822,772 Edwards Feb. 11, 1958 2,889,790 Smith et al June 9, 1959 

